a Department of Chemistry, University of Patras, Patras 26220, Greeceb Department of Chemistry, University of Calgary, Alberta, Canada T2N 4N1c Department of Medical Biochemistry, University of Calgary, Alberta, Canada T2N 4N1

Abstract

The conformational properties of the Sarmesin analogues [N-MeAib1, Tyr(Me)4]ANGII and [N-MeAib1, Tyr(Me)4, Ile8]ANGII in hexadeutero-dimethysulfoxide were investigated by Nuclear Overhauser Effect (NOE) Enhancement Studies. Cis-trans isomers (ratio 1 : 6) due to restricted rotation of the His-Pro bond were observed. Interresidue interactions between the His Cαproton and the two Pro Cδ protons revealed that the major isomer was the trans.